The present invention relates generally to a zoom optical system and electronic equipment incorporating the same, and more particularly to a compact zoom optical system and electronic equipment incorporating the same. The electronic equipment contemplated herein, for instance, includes digital cameras, video cameras, digital video units, personal computers, mobile computers, cellular phones and personal digital assistants.
Some optical systems have been proposed for zoom image pickup optical systems made up of free-form surface prisms.
One of those optical systems is designed to move a plurality of prisms for zooming. This arrangement has to previously have a prism movement space therein.
Another optical system is designed to move an aperture with respect to a prism to vary the position of incidence of light rays for zooming. However, this optical system, because of being adapted to from a primary image, becomes bulky. In addition, not only a movement mechanism but also a mechanism for varying an aperture diameter is needed to allow the aperture to have a brightness control function.
Yet another optical system, too, becomes bulky because of being adapted to form a primary image. For zooming, an image-side prism is rotated with the center of rotation on the position of the primary image, resulting in an increase in the amount of movement in association with the rotation of the image-side prism.